SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fa28a2029483cb6bea774989c7a2705d451e6863ff915641579acd15c0fe314' 
  AND token = '9xVTXrLpec3VZknTxpNtKjVGbfipbJAM7s78s4Zw1zw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}